Laser projector

ABSTRACT

A laser projector steers a pulsed laser beam to form a pattern of stationary dots on an object, the pulsed laser beam having a periodicity determined based at least in part on a maximum allowable spacing of the dots and on a maximum angular velocity at which the beam can be steered, wherein a pulse width of the laser beam and a pulse peak power of the laser beam are based at least in part on the determined periodicity and on laser safety requirements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 17/028,398 (filed Sep. 22, 2020), which claims the benefit ofU.S. Provisional Application Ser. No. 62/925,257 (filed Oct. 24, 2019)and U.S. Provisional Application Ser. No. 62/935,709 (filed Nov. 15,2019), the contents of both of which are incorporated herein in theirentirety.

BACKGROUND

The subject matter disclosed herein relates to a light projectionsystem, often referred to as a “laser projector,” and especially to alight projection system that projects a glowing light pattern onto anobject without requiring retroreflective or cooperative targets.

Light projection devices are used in a variety of applications toproject images onto objects. In some applications, an illuminatedthree-dimensional (3D) pattern, also referred to as a “template,” isprojected onto an object. The template may be formed, for example, byprojecting a rapidly moving, vector-scan, light beam onto the object. Insome systems, the projected light beam is a laser beam. The light beamstrikes the surface of the object following a predetermined trajectoryin a repetitive manner. When repetitively moved at a sufficiently highbeam speed and refresh rate, the trace of the projected beam on theobject appears to the human eye as a continuous glowing line. Theprojected pattern of light appears as the glowing template that can beused to assist in the positioning of parts, components and work pieces.

Currently, light projection systems are mainly used within productionfacilities. Light projection systems potentially useful outsideproduction facilities, for example, in construction sites to assist inconstructing of buildings or other objects. However, until now,limitations have made the use of light projection devices impractical insuch applications. Examples of such limitations include (1) powerlimitations that make battery operation largely impractical, (2)cumbersome sharing of information with computers and accessoryinstruments, (3) relatively large instrument size, and (4) dynamic rangelimitations making many types of measurements impractical. In addition,a problem seen within production facilities and outdoors at constructionsites is poor visibility of projected laser beams in certaincircumstances, particularly when distances being measured are large,when flicker cannot be tolerated, and when laser safety standards aredesired be observed.

Accordingly, while light projection systems and methods are suitable fortheir intended purposes, the need for improvement remains, particularlyin enabling power efficient battery operation, methods of easily sharingdata with computers and instruments, reducing instrument size,increasing measurement dynamic range, and maintaining high visibility ofprojected light.

BRIEF DESCRIPTION

According to an embodiment, a method is provided. The method includes:steering a pulsed laser beam to form a pattern of stationary dots on anobject, the pulsed laser beam having a periodicity determined based atleast in part on a maximum allowable spacing of the dots and on amaximum angular velocity at which the beam can be steered, wherein apulse width of the laser beam and a pulse peak power of the laser beamare based at least in part on the determined periodicity and on lasersafety requirements; and storing the periodicity.

In addition to one or more of the features described herein, or as analternative, further embodiments of the method may include steering acontinuous-wave (cw) laser beam to form a pattern on the object, thepower of the emitted laser beam based at least in part on the lasersafety requirements. In addition to one or more of the featuresdescribed herein, or as an alternative, further embodiments of themethod may include shutting off projection of laser light in response todetecting with an optical detector a condition indicating that theemitted laser pulse energy has exceeded a laser safety limit. Inaddition to one or more of the features described herein, or as analternative, further embodiments of the method may include shutting offprojection of laser light in response to detecting with an opticaldetector a condition indicating that the emitted average laser power hasexceeded a laser safety limit.

In addition to one or more of the features described herein, or as analternative, further embodiments of the method may include placing areflective target to intercept one of the dots; and detecting a changein reflected light and, in response, switching the laser from pulsedmode to continuous-wave (cw) mode. In addition to one or more of thefeatures described herein, or as an alternative, further embodiments ofthe method may include detecting a second pattern of laser lightreflected from the reflective target when the laser is in cw mode and,in response, taking an action based on the detected second pattern.

According to another embodiment a device is provided. The deviceincludes: a laser operable to produce a pulsed laser beam; abeam-steering system operable to steer the pulsed laser beam onto anobject; and one or more processors operable to control the laser and thebeam-steering system to form the pulsed laser beam into a pattern ofstationary dots on the object, the pulsed laser beam having aperiodicity determined based at least in part on a maximum allowablespacing of the dots and on a maximum angular velocity at which the beamcan be steered, the pulsed laser beam having a pulse width and a pulsepeak power of the laser beam determined based at least in part on thedetermined periodicity and on laser safety requirements.

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include the laserbeing further operable to produce a continuous-wave (cw) laser beamhaving an emitted power, the emitted power based at least in part on thelaser safety requirements; and the beam-steering system is furtheroperable to steer the cw laser beam onto the object to form a pattern onthe object. In addition to one or more of the features described herein,or as an alternative, further embodiments of the device may include theone or more processors are further operable to shut off the projectionof laser light in response to detecting with an optical detector acondition indicating that the emitted laser pulse energy has exceeded alaser safety limit. In addition to one or more of the features describedherein, or as an alternative, further embodiments of the device mayinclude the one or more processors are further operable to shut off theprojection of laser light in response to detecting with an opticaldetector a condition indicating that the emitted average laser power hasexceeded a laser safety limit. In addition to one or more of thefeatures described herein, or as an alternative, further embodiments ofthe device may include the action including steering the pulsed laserbeam to form a third pattern of stationary dots on the object, the thirdpattern covering a smaller area than the first pattern.

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include a reflectivetarget; and an optical detector operable to detect reflected laserlight. In addition to one or more of the features described herein, oras an alternative, further embodiments of the device may include thelaser being further operable to produce a continuous-wave (cw) laserbeam; the beam-steering system is further operable to steer the cw laserbeam onto the object to form a pattern on the object; and the one ormore processors are further operable to determine that laser lightdetected by the detector has been reflected by the reflective targetand, in response, causing the laser to emit the cw laser beam andfurther causing the beam-steering system to steer the emitted cw laserbeam into a segment of light on the reflective target.

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include the one ormore processors are further operable to determine that the cw laserbeam, when reflected from the reflective target and detected by theoptical detector, has a second pattern, the processor taking a furtheraction based on the determined second pattern. In addition to one ormore of the features described herein, or as an alternative, furtherembodiments of the device may include the further action includingsteering the pulsed laser beam to form a third pattern of stationarydots on the object, the third pattern covering a smaller area than thefirst pattern.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF DRAWINGS

The subject matter, which is regarded as the disclosure, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe disclosure are apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings in which:

FIGS. 1A, 1B are two isometric views of a light projection systemaccording to an embodiment;

FIG. 2 is an isometric view of the light projection system with its fancooling system removed according to an embodiment;

FIG. 3 is an exploded view of a front-panel assembly of a lightprojector according to an embodiment;

FIGS. 4A, 4B are front and rear isometric view of a rear panel assemblyaccording to an embodiment;

FIG. 5 is an isometric view of an opened power-battery compartmentaccording to an embodiment;

FIGS. 6A, 6B are isometric views of a fan assembly according to anembodiment;

FIG. 7 is a partially cross-sectional, front interior view of the lightprojection system according to an embodiment;

FIG. 8 is a schematic representation of optical elements of the lightprojection system according to an embodiment;

FIG. 9 is a front cross-sectional view of elements in the lightprojection system according to an embodiment;

FIG. 10 is a front view of optomechanical elements of the lightprojection system according to an embodiment;

FIG. 11 is an isometric view of optomechanical elements of the lightprojection system according to an embodiment;

FIG. 12 is an exploded isometric view of an optics housing according toan embodiment;

FIG. 13 is an exploded isometric view of a return optics assemblyaccording to an embodiment;

FIG. 14 is an exploded isometric view of a focusing assembly accordingto an embodiment;

FIG. 15 is an isometric view of optomechanical elements of the lightprojection system, including an optoelectrical control board, accordingto an embodiment;

FIG. 16 is cross-sectional side view of the light projection systemaccording to an embodiment;

FIG. 17 is a block diagram of electrical modules of the light projectionsystem according to an embodiment;

FIG. 18A is an electrical block diagram for an optics module accordingto an embodiment;

FIG. 18B is an electrical block diagram for a front panel module and alaser module according to an embodiment;

FIG. 18C is an electrical block diagram for an electronics module, agalvo module, and a back-panel module according to an embodiment;

FIG. 18D is an electrical block diagram for a power/battery moduleaccording to an embodiment;

FIG. 19 is a schematic representation of a light projection systemprojecting patterns of light onto an object according to an embodiment;

FIG. 20 is an exemplary pair of plots showing a trapezoidal velocityprofile and resulting position profile according to an embodiment;

FIG. 21 is an exemplary plot showing beam steering trajectory controlusing free running motion control ticks according to an embodiment;

FIG. 22 is an exemplary projection pattern in which beam steering motionis synchronized with a stream of laser pulses according to anembodiment;

FIG. 23A is a schematic illustration of brightness of a projected laserline for a continuous wave (cw) laser beam according to an embodiment;

FIG. 23B is a schematic illustration of illumination distribution for apulsed beam traveling at a constant velocity according to an embodiment;

FIG. 23C is a schematic illustration of brightness of a projected laserline for a pulsed laser beam according to an embodiment;

FIG. 23D is a schematic illustration of laser pulses according to anembodiment;

FIGS. 24A, 24B, 24C are schematic illustrations of three different codedpatch patterns according to an embodiment;

FIG. 24D is a schematic illustration of a patch in the vicinity ofstationary projected light spots; and

FIG. 24E is a schematic illustration of a patch in the vicinity of a cwprojected light beam according to an embodiment.

The detailed description explains embodiments of the disclosure,together with advantages and features, by way of example with referenceto the drawings.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide improved power efficiency,built-in batteries, wireless communication, reduced instrument size,improved dynamic range, and higher visibility of projected patternswithout flicker.

FIGS. 1A, 1B are front isometric and rear isometric views of a lightprojector 10 according to an embodiment. In an embodiment, the lightprojector 10 includes a front cover assembly 20, a base assembly 30, apower assembly 40, and a fan assembly 50. The power assembly 40 furtherincludes a latch 42 that opens and closes a door 44. In an embodiment,elastomeric bumpers 22 are attached to each of the four corners of thefront cover assembly 20 and light pipes 24 are attached on each side ofeach bumper. The light pipes are illuminated by light emitting diodes(LEDs) in status LED PCBAs 340 (FIG. 3 ).

FIG. 2 is an isometric view of the light projector with the fan assemblyremoved. A rear assembly 60 is sandwiched between the base assembly 30and the power assembly 40. The base assembly 30 and the rear assembly 60include grooved heat sinks 35 as outer elements.

FIG. 3 is an exploded isometric view of the front cover assembly 20. Inan embodiment, the front cover assembly 20 includes a front panelsubassembly 310, status LED printed circuit board assemblies (PCBAs)340, and camera subassembly 360. The front panel subassembly 310includes a front panel form 312, an information plate 314, a frontwindow 316, a window gasket 318, a camera illuminator gasket 320, and acamera window 322. The front cover assembly 20 includes four of thestatus LED PCBAs 340, one of the PCBAs 40 behind each corner of thefront panel form 312. In an embodiment, the camera subassembly 360includes a camera lens 362, a camera lens mount 364, a camera PCBA 366,and an infrared (IR) LED PCBA 370. The camera PCBA 366 includes aphotosensitive array, and the IR LED PCBA 370, which includes LEDs 372.

FIGS. 4A, 4B show two isometric views of the rear assembly 60. The rearassembly 60 includes a rear panel 410, a power distribution PCBA 420, aribbon cable 422, an environmental recorder 430, and an internal battery440. The ribbon cable, which has first header 423 and second header 424,receives electrical power from and exchanges communication signals withthe power assembly 40. The rear panel 410 serves as a grooved heat sink.

FIG. 5 is a partially exploded isometric view of the power assembly 40that includes the door 44 opened to reveal two battery units 510, 512and a circuit board compartment 520. In an embodiment, the batteries510, 512 may be removed or inserted without turning off power to thelight projector 10. The power assembly further includes an on-off switch530, a connector for optional input power 522, and an Ethernet connector524.

FIGS. 6A, 6B are top isometric and bottom isometric views, respectively,of a fan assembly 50. From the top isometric view, FIG. 6A shows the fanplenum 610, which is the part of the fan assembly that circulates air tocomponents of the light projector 10. The fan assembly further includestwo cooling fans 620, 622 and a cooling fan mount 624.

FIG. 7 is a front view of the base assembly 30. In this view, somecomponents are shown in cross section, including the base housing 702,the fan assembly, and optical components such as lenses, beam splitters,and detectors. A laser 710 launches polarized light into a polarizationmaintaining (PM) optical fiber 712, which terminates in a fiber-opticconnector 714 that includes a ferrule 716. Light is launched from theferrule 716 through a first lens assembly 720 and a second lens assembly725. A focusing mechanism 730 adjusts the position of the second lensassembly 725 to focus the beam of light to a small spot on an objectsome distance away from the light projector 10. The light from thesecond lens assembly 725 proceeds to a folding beam splitter 740. Asmall amount of the light passes to an optical detector 742 thatmeasures the optical power of the launched laser beam for monitoringpurposes. The rest of the laser light reflects off the folding beamsplitter 740 and travels to the polarizing beam splitter 745.

In an embodiment, the ferrule 716 is clocked to align the linearpolarization of the laser light to the direction of maximum reflectionof the polarizing beam splitter 745. The light reflected off thepolarizing beam splitter 745 passes through a quarter wave plate 750oriented to convert the reflected linearly polarized light intocircularly polarized light. The circularly polarized light reflects offa first mirror 755 driven by a galvanometer (galvo) motor assembly 757that further includes a transducer such as an angular encoder (notshown) for measuring the angle of rotation of the first mirror 755. Thelight reflected off the first mirror 755 passes to a second mirror 760that sends the light out of the window 316. The second mirror 760 isdriven by the galvo motor assembly 762 that further includes an angulartransducer (not shown) for measuring the angle of rotation of the secondmirror 760.

After striking an object, reflected light passes back through the window316, reflects off the second mirror 760, reflects off the first mirror755, and passes back through the quarter wave plate 750. In reflectingoff the object, the handedness of the circularly polarized light isreversed. As a result, when passing through the quarter waveplate on thereverse path, the light is converted back to linear polarizationoriented at 90 degrees with respect to the outgoing beam of lightreflected off the polarizing beam splitter 745. The returning lightreaching the polarizing beam splitter 745 is oriented in the directionof minimum reflection (maximum transmission) of the polarizing beamsplitter 745, enabling the returning light passes through the polarizingbeam splitter 745 with low loss. This arrangement of using a quarterwave plate in combination with a linearly polarizing beam splitter toreduce loss provides a advantage over prior art light projectors. In theusual light projector system, half of the light is lost on a beamsplitter on the way out of the light projector and half of the light islost on the beam splitter on the way back into the light projector. Inother words, with the quarter wave plate method described herein, thereturning light level may increase by a factor of four than wouldotherwise be the case.

The returning light passes through an optical bandpass filter 765 thatrejects wavelengths outside a narrow band around the projected laserwavelength. In an embodiment, the laser 710 emits light at 520 nm, andthe bandpass filter is also centered at 520 nm. A lens 770 focuses thelight, which passes through a pinhole 775 before traveling to a beamsplitter 780. In an embodiment, the beam splitter 780 transmits 80percent of the light and reflects 20 percent of the light. In anembodiment, part of the light is transmitted to a relatively highsensitivity silicon photomultiplier (SiPM) detector 785, and anotherpart of the light is reflected to a relatively low sensitivity SiPMdetector 790. In an embodiment, the higher sensitivity detector isapproximately one thousand times more sensitive than the lowersensitivity detector. By providing two SiPM detectors having differentsensitivities, a greater variety of objects can be measured with ascanned laser beam. A range of detector sensitivities is useful, forexample, in measuring near objects and far objects and in measuringobjects having reflectance ranging from high to low.

In sending the light from the folding beam splitter 740 to thepolarizing beam splitter 745, a small amount of light may be transmittedthrough the beamsplitter. A beam dump 795 absorbs this small amount oflight, minimizing any stray, unwanted light. In an embodiment, the beamdump 795 includes an anti-reflection (AR) coated neutral density (ND)filter 796 and a low-reflectance block 797 such as black felt.

FIG. 8 is a schematic representation of optical elements included inFIG. 7 , with numbering of all optical elements the same as in FIG. 7 .FIG. 9 is a cross-sectional view of optical components and theiroptomechanical supports, with numbering of elements the same as in FIG.7 . FIG. 10 is a top view and FIG. 11 is an isometric view of opticalcomponents and their optomechanical supports, with the numbering ofelements the same as in FIG. 7 . A first optics tube 1010 supports thefirst lens assembly 720 and the second lens assembly 725. A focusstepper mount 1012 affixes the first optics tube 1010 to the focusingmechanism 730. A tube clamp 1014 affixes the first optics tube 1010 tothe beam splitter housing 1030. A power monitor assembly 1020 thatincludes an optical detector 742 is attached to the beam splitterhousing 1030. An adapter mount 1032 attaches the quarter wave plate 750to the beam splitter housing 1030. In addition, the polarizing beamsplitter 745, the AR coated ND filter 796, the low-reflectance block797, and a second optics tube 1040 attach to the beam splitter housing1030. A pinhole-adjuster assembly 1050 provides an interface between thesecond optics tube 1040 and an SiPM detector assembly 1060. FIG. 12 isan exploded isometric view of the beam splitter housing 1030 andattached components numbered as in FIG. 7 . Optical detector PCBA 741includes the optical detector 742 (FIGS. 7, 8 ).

FIG. 13 is an exploded isometric view of a return optics assembly 1300that includes a retaining ring 1302, the optical bandpass filter 765, aspacer 1304, the lens 770, the second optics tube 1040, a wave spring1310, the x-y adjustment assembly 1050, a z-alignment ring 1320, an NDfilter 1330, a dual-sensor mount 1340, the beam splitter 780, a firstSiPM PCBA 1390, and a second SiPM PCBA 1385. In an embodiment, the firstSiPM PCBA 1390 includes the relatively low sensitivity SiPM detector790, while the second SiPM PCBA 1385 includes the relatively highsensitivity SiPM detector 785. The pinhole-adjuster assembly includes anx-y adjustment assembly 1050, which is coupled to a z-adjustmentassembly that includes the second optics tube 1040, the z-alignment ring1320, and the wave spring 1310. The pinhole aperture is a small platehaving a small hole, ordinarily less than 100 micrometers in diameter.The x-y adjustment assembly 1050 includes a threaded x hole 1051 and asimilar hole on the opposite side of 1051. In an embodiment, acompression spring is placed in one of these holes followed by a setscrew. A set screw is screwed into the opposite threaded x hole. Byadjusting the positions of the set screws, the pinhole can be adjustedin the x direction. The x-y adjustment assembly 1050 further includes athreaded y hole 1052 and a similar hole on the opposite side of 1052. Inan embodiment, a compression spring is placed in one of these holesfollowed by a set screw. A set screw is screwed into the oppositethreaded y hole. By adjusting the positions of the set screws, thepinhole can be adjusted in the y direction. The x-y adjustment stageslides into the z-alignment ring 1320 until the edge 1053 of the x-yadjustment stage encounters the circular ridge 1054 of the z-alignmentring 1320. With the x-y stage in this position, the holes 1051, 1052 areaccessible allowing the x-y adjustment to be made after the attachmentto the z-alignment ring. The z-alignment ring has an internal threadthat matches the external thread of the second optics tube 1040. Thewave spring 1310 is placed against the x-y adjustment ring 1050. Thespring provides a force to keep the edge 1053 in contact with thecircular ridge 1054 as the z-alignment stage is screwed in and out toobtain the proper pinhole aperture position in the z-direction. Across-sectional view of the elements of the pinhole aperture and pinholeadjustment assembly is shown FIG. 9 .

By adjusting the set screws, the pinhole aperture can be centered on thereturning light. The pinhole aperture 775 (FIGS. 7, 8, 9 ) helps toblock unwanted background light from the environment outside theenclosure of the light projector 10. Examples of such unwantedbackground light blocked by the aperture include artificial light andsunlight, both direct and reflected. In a further embodiment, the framethat holds the lens and pinhole assembly is at least partially coveredwith a coating to suppress reflections from the light traveling betweenthe lens 770 and the pinhole 775. In the embodiment illustrated in FIG.9 , the inner elements of the frame that may be coated include an innerportion of the second optics tube 1310 and an inner portion of the x-yadjustment assembly 1050. In an embodiment, the coating applied to theinner elements of the frame is a material such as Acktar Magic Blackcoating that can reduce reflections from metal to about one percent forvisible wavelengths. Acktar Ltd. Has its headquarters in Kiryat-Gat,Israel.

FIG. 14 is an exploded isometric view of the focusing mechanism 730,along with components attached to and actuated by the focusing mechanism730. The focusing mechanism includes a stepper motor 1410, a retainingring 1412, the focus stepper mount 1012, a spring 1420, an oversizedwasher 1430, a focus slide connector 1440, a lock washer 1416, and a nut1418. Elements attached to the focusing mechanism 730 include the tubeclamp 1014, the first optics tube 1010, the first lens 720, a retainingring 1414, and a sliding focus assembly 1450. FIG. 9 shows across-sectional view of the three elements of the sliding focus assembly1450, which include the sliding focus mount 1451, the second lens 725,and the retaining ring 1452. The sliding focus mount 1451 is attached tothe focus slide connector 1440 with a screw 1453, as shown in FIG. 9 .The stepper motor 1410 includes a threaded portion 1411 that passesthrough hole 1441 in the focus slide connector 1440. The lock washer1416 and nut 1418 attach to the threaded portion 1411 of the steppermotor. The spring 1420 and the oversized washer 1430 provide compressiveforce to hold the focus slide connector 1440 firmly to against the lockwasher 1416. The focus slide connector 1440 also includes a rod 1444used to trigger a photogate sensor when setting a home position for thefocus slide connector 1440.

The purpose of the focusing mechanism 730 is to focus the beam of lightfrom the light projector 10 on an object of interest. A method formaking this adjustment using a focusing mechanism is described incommonly owned U.S. patent application Ser. No. 16/017,360 filed on Jun.25, 2018 (Attorney Docket FAO0893US), the contents of which areincorporated by reference herein.

FIG. 15 is an isometric view of the optical components and theiroptomechanical supports as shown in FIG. 14 with the addition of anoptoelectrical control board 1400. The optoelectrical control boardincludes electrical circuits to cooperate with PCBAs having opticaldetectors 742, 785, and 790. It also includes electrical circuits tocontrol the focusing mechanism 730.

FIG. 16 is a cross-sectional side view of the light projector system 10.Shown are the front cover assembly 20, the base assembly 30, the powerassembly 40, the fan assembly 50, and the rear assembly 60. The baseassembly includes the base housing 702, an outer portion of whichincludes the grooved heat sinks 35. Shown within the base assembly 30are the optoelectrical control board 1400, some optical andoptomechanical components, and some PCBAs 1610. The power assembly 40includes batteries 510, 512, and the circuit board compartment 520. Thefan assembly 50 includes the fan plenum 610 and a cooling fan 620. Therear assembly 60 includes the rear panel 410 and the power distributionPCBA 420.

FIG. 17 is a block diagram of electrical modules 1700 within the lightprojection system 10 according to an embodiment. Each module may beconstructed and tested separately from the other modules. In most cases,each module includes a PCBA. Electrical modules 1700 include opticsmodule 1710, front panel module 1720, laser module 1730, electronicsprocessing module 1740, galvo module 1750, back-panel module 1760,power/battery module 1770, and fan module 1780.

FIG. 18A is a block diagram of electrical elements of the optics module1710. In an embodiment, the optics module 1710 includes the first SiPMPCBA 1390, the second SiPM PCBA 1385, the optical detector PCBA 741.Electrical signals from the first SiPM PCBA 1390 and the second SiPMPCBA 1385 go to an analog section 1802 that includes a transimpedanceamplifier and other electrical conditioning components. The analogsection 1802 includes an analog-to-digital converter (ADC) that convertsthe processed analog signals to digital signals for transmission to acomplex programmable logic device (CPLD) 1810 for further processing.The processed signals from the CPLD 1804 pass over wires to thecarrier-opto controls connector 1810A. Electrical signals pass betweenthe carrier/opto-controls connector 1810A over a cable 182 to acarrier/opto-controls connector 1810B on the electronics processingmodule 1740. The electrical signal from the optical detector PCBA 741 issent to power monitor 1820, which provides processed data to a processordevice, which in an embodiment is a programmable system-on-a-chip (PSoC)1825. A PSoC is a family of microcontroller integrated circuitsmanufactured by Cypress Semiconductor, a company having headquarters inSan Jose, Calif. Other types of processor devices different than a PSoCmay be used in place of the PSoC 1825. In an embodiment, the PSoC 1825sends signals to an I2C controller 1830 that sends one set of controlsignals 1831 to the four status LED PCBAs 340 and other signals 1832 tothe IR LED PCBA 370. The PSoC 1825 also sends signals to a steppercontroller 1835 that sends signals to the stepper motor 1410, whichadjusts the position of the second lens 725 to focus the projected lighton an object. The home switch 1837 sets a home position by triggeringwhen the rod 1444 passes in front of a photogate sensor.

FIG. 18B is a block diagram of electrical elements of the front panelmodule 1720 and the laser module 1730. The laser module 1730 includes alaser 1733 having a built-in thermistor 1734 and in contact with athermoelectric controller (TEC) 1735. The laser 1733 and built-inthermistor 1734 are included in the laser 710 (FIG. 7 ). The lasermodule 1730 further includes a TEC PCBA 1731, and a laser driver PCBA1732. Power is provided to the TEC PCBA 1731 over the line 1840 from theoptics module 1710. Additional power is supplied to the laser driverPCBA 1732 by the +12 V supply over the line 1843. on the optics moduleprovides power to the TEC PCBA 1731 over the line 1840. The laser driverPCBA receives additional control signals via control line 1841 from thePSoC 1825 and 1842 from the cable 1811. The thermistor 1734 measures thetemperature of the laser 1733 and provides the measured temperature tothe TEC PCBA 1731, which adjusts the TEC 1735 to hold the lasertemperature to a desired set point.

FIG. 18C is a block diagram of electrical elements of the electronicsprocessing module 1740, the galvo module 1750, and the back-panel module1760. The electronics processing module 1740 includes a carrier PCBA1845 for a System-On-Module (SOM) 1850 and a collection of additionalelectrical components that interface with the SOM. In an embodiment, theSOM is a PicoZed, a device sold by Avnet and based on models of XilinxSystem-on-a Chip (SoC). Avnet has its headquarters in Phoenix, Ariz.Xilinx has its headquarters in San Jose, Calif. The SOM 1850 is placedon the carrier PCBA 1845 that includes a Wi-Fi and Bluetooth component1852 that interfaces with an antenna 1853. The SOM 1850 also supports aWi-Fi LED PCBA 1854. Wi-Fi is a trademark of the non-profit Wi-FiAlliance. Wi-Fi devices are compliant with the IEEE 802.11 standard.Bluetooth is a wireless technology standard used for exchanging databetween fixed and mobile devices over short distances using radio wavesbetween 2.4 and 2.485 GHz. Bluetooth standards are maintained by theBluetooth Specification Working Group (CSWG). The Wi-Fi may be used as aclient to interface with already established network or as an accesspoint for establishing links to computers or other instruments notconnected to a network. The carrier PCBA 1845 supports a laser powerswitch 1855 for turning the laser 710 on and off. The carrier PCBA 1845includes low-voltage differential signaling (LVDS) circuitry 1857 to thestandard RS-422, also known as TIA-EIA-422. This technical standardspecifies the electrical characteristics of a differential, serialcommunication protocol. The SOM supports Ethernet and is interconnectedthrough the ribbon cable 422 to the Ethernet connector 524 on the powerassembly 40. The first header 423 for the ribbon cable 422 resides inthe back-panel module 1760. The carrier module 1845 further includes aMicroSD card slot 1860 that enables reading and writing of data onMicroSD cards. In an embodiment, the SOM 1850 communicates with thecamera PCBA 366 over a Universal Serial Bus (USB) link 1722. USB is anindustry standard maintained by the USB Implementer's Forum.

The back-panel module 1760 includes an environmental logger PCBA 430that in an embodiment includes two accelerometers for measuring twodifferent maximum acceleration levels. It also includes a combinationhumidity/temperature sensor, an oscillator to drive a real-time clock,and nonvolatile memory for logging extreme events with time stamps. Suchextreme events may include large shocks, relatively very hightemperatures or humidities or relatively very low temperatures. Abattery 440 is provided to power the elements in the environmentallogger PCBA 430 even when the power to the unit is turned off— forexample, when a unit is shipped with batteries removed. The battery 440also provides short term power for the carrier PCBA 1845 for around aminute when batteries 510, 512 are removed and electrical power isotherwise not provided. In this way, state information for the system ispreserved long enough to allow a battery to be exchanged. The battery440 also provides power to an 8-bit microcontroller 1864 that isattached to a nine-axis MEMS inertial measurement unit (IMU) 1865.

FIG. 18D is a block diagram of the power/battery module 1770. The ORcontroller 1870 cooperates with the power prioritizer 1867 and the mainload switch 1866 to determine the amount of current, if any, drawn fromeach of the first battery 510 and the second battery 512. Some of theresulting power is provided to DC-DC converter 1862 that produces −15volts and DC-DC converter 1863 that produces +15 volts. These voltagesare provided to the digital signal processor (DSP) in the galvo module1750. AC power is provided through the input port 522, which is sent toan electrical input filter PCBA 1872 and on to an AC-DC converter 1874that convert AC voltages between 100 and 240 VAC into a DC voltage of+15 VDC. The Ethernet input signal is sent to a magnetics unit 1876 thatserves as an isolation transformer for the Ethernet signal. An LEDdriver 1878 provides signals to a first battery LED status indicator orDSP 1890 and a second battery LED status indicator or DSP 1892.

FIG. 18C shows the electrical elements of the galvo module 1750 thatsupport the galvo motor assemblies 757, 762. In an embodiment, theelectronics of the galvo module make use of electrical and algorithmicmethods to reduce the power consumed by the galvo motors whilecontinuing to provide high visibility in the pattern of light projectedby the light projector 10. Methods for obtaining this power reductionare described in commonly owned U.S. Patent Application No. 62/925,257filed on Oct. 24, 2019 (Attorney Docket FAO0925US), the contents ofwhich are incorporated by reference herein. These methods includeadjusting the output of a power control module based at least on one ormore calculated parameters that control the trajectory of the projectedbeam of light on the object. In an embodiment shown in FIG. 18C, a poweramplifier 1882 drives an XY galvo module 1884 that controls themovements of the galvo motor assemblies 757, 762. In an embodiment, theparameter-based trajectory is determined at least in part by the DSP1880. In an embodiment, one of the calculated parameters is the refreshrate for the flicker-free threshold of the projected beam of light. Inan embodiment, the power amplifier 1882 is a switching mode currentamplifier having an output based on a configurable effective duty cycle.

In FIG. 19 , the light projector 10 projects a glowing pattern of light1910 onto an object of interest 1920. This glowing pattern of light issometimes referred to as a “template.” In general, the projected patternof light 1910 is repeated periodically at a given time interval, whichis the period of the projected pattern. The reciprocal of the period ofthe projected pattern is called the refresh rate. If the refresh rate istoo low, the glowing pattern will appear to observers to be flickeringand will appear to flash at regular intervals. A flickering pattern cancause observers to experience fatigue, dizziness, and headaches. Toavoid this problem, the refresh rate is set high enough that a viewerobserves the glowing pattern as a steady, flicker-free image. Such aflicker-free image is related to persistence of vision experienced whenviewing motion pictures in cinema or on television. In some embodiments,it is also desired that the projected glowing pattern of light 1910 bebright enough to be clearly visible to an observer. At the same time, itis desired that a glowing pattern of light 1910 meet the eye safetylimit for laser light.

In addition to projecting a glowing pattern of light 1910 on an objectof interest 1920, light projectors 10 are also used to scan fiducialtargets such as the targets 1930A, 1930B, 1930C, 1930D with the samebeam 1905 used to produce the glowing pattern of light 1910. In somecases, the fiducial targets have been made of retroreflective materials,while in other cases the targets are features that are reflective butnot retroreflective.

Historically, industrial light projector systems have used continuouswave (cw) lasers with on/off controls to project multi-segment glowingtemplates. However, the visibility of a glowing pattern of light 1910produced by a cw laser is limited by the allowable average laser beampower. The visible brightness of projected continuous lines isproportional to the reflectivity of the object's surface and inverselyrelated to the projected line width and the distance from the projectorto the object.

A prior art reference disclosing improvement of laser projectionvisibility is disclosed in U.S. Pat. No. 7,385,180 to Rueb, et al.,issued on Jun. 10, 2008. The suggested solution prescribes decreasingthe maximum beam steering speed, resulting in a flickering image.Although such an approach increases visibility, it does so at theexpense of user headaches and dizziness.

A prior art approach to improving visibility without flickering isdisclosed in commonly held U.S. Pat. No. 8,085,388 to Kaufman, et al.,issued on Dec. 27, 2011. This approach uses a pulsed laser, such as aQ-switched laser, having a fixed repetition rate. A beam-steeringcontrol is synchronized with the generated laser pulses to produce aprojection consisting of stationary spots 1912. Although an improvementover prior art solutions, this approach could not be optimized todeliver the best possible visibility of the projected laser light fordifferent trajectories of the projected beam while also meeting eyelaser safety requirements. Another shortcoming of this approach is theneed for relatively complicated and expensive signal processing.

In an embodiment, the glowing pattern of light 1910 includes dottedcontours 1912 as in FIG. 19 . In an embodiment, the dots 1912 appear tobe stationary to the human eye though the projected trajectory iscreated by dynamically steering the laser beam as a periodic function oftime. In an embodiment, the dots 1912 are formed by pulsed laser lighthaving a selectable repetition rate. A beam steering control producesvariable acceleration and velocity through a stream of incrementalposition commands precisely synchronized with the timing of the laserpulses. The frequency and duration of the laser pulses are selectedbased at least in part on a selected beam angular velocity thatmaintains a reasonable separation between the dots while maintaining apeak optical power that meets the laser eye safety limits. To implementsuch a collection of dots with the light projection system 10. In anembodiment, the laser 710 has modes for generating both pulsed light andcw light. In an embodiment, the pulsed laser light may rapidly changerepetition rate, peak power, and pulse duration. In an embodiment, thecw laser has a variable power level. In an embodiment, the laser sourceis a semiconductor laser having analog functionality for modulating thelaser beam in time. In an embodiment, the light projector 10 ordinarilyuses the pulsed mode of operation when projecting the glowing pattern oflight 1910 on the object as a collection of dots 1912. It ordinarilyuses the cw mode of operation when scanning fiducial targets andfeatures such as 1930A, 1930B, 1930C, 1930D in raster scan patterns1932A, 1932B, 1932C, 1932D, respectively. In an embodiment, the analogsection circuit 1802 (FIG. 18A) converts the detected signal from analogto digital form before sending it to the CPLD 1804 for furtherprocessing. In an embodiment, the optical detector 741 and the powermonitor 1820 are used to guarantee fail-safe system operation inmultiple laser control modes by limiting the average output power and,if desired, the laser pulse energy according to the assigned lasersafety class.

In an exemplary light projector 10, the beam steering angular velocityreaches up to about 200 radians per second, with beam steering angularaccelerations reaching up to about 200,000 radians per second squared.FIG. 20 illustrates an exemplary velocity trajectory 2010 constructed ofpiece-wise segments. FIG. 20 also shows the resulting positiontrajectory 2020, which is found by integrating the velocity trajectoryover time. In an embodiment, beam-steering servo control is provided bythe DSP 1880 of the galvo module 1750 (FIG. 18C). In an embodiment, theDSP 1880 sends real-time position commands to the galvo motor assemblies757, 762 at equal time intervals (“time ticks”) of between 10 and 80microseconds. Because the time intervals are much smaller than thereaction time of the galvo motor assemblies 757, 764, the positioncommands executed in each time interval produce a smooth motion. This isillustrated in FIG. 21 , where incremental position movements at timeintervals T produce a smooth position trajectory 2110.

In an embodiment, the carrier PCBA 1845 provides a master clock thatsends synchronization signals to the DSP 1880 in the galvo module 1750and through the cables 1811, 1842 to the TEC PCBA 1731. FIG. 22 is aschematic illustration showing how galvo movements and laser emissionsare synchronized to produce a glowing pattern 2210 on an object. Theglowing pattern includes a collection of glowing dots 2212. A line 2214connecting the dots is ordinarily not visible on the object. In anembodiment, a complete collection of the dots 2212 is projected onceeach cycle beginning with an initial projection point 2216. In anembodiment, both galvo mirrors 755, 760 are completely settled in theirpositions at the initial projection point 2216. The direction ofmovement of the projected dots during a cycle is indicated by the arrows2218. Clock pulses 2222 of the master clock pulse train 2220 areseparated by the time intervals (time ticks) T. In an embodiment, thelaser beam is emitted at each time interval, with one of the dots 2212produced with each emission. In an embodiment, the amount of separationbetween adjacent dots 2212 is determined by the movement of the galvomirrors 755, 760 between laser emissions. In an embodiment, thismovement is determined by signals sent from the DSP 1880 to the poweramplifier 1882 in the galvo module 1750. These signals are indicative ofa position trajectory 2230 in FIG. 22 , also discussed herein inreference to FIG. 21 . The distance between successive dots 2212 arecommand increment distances 2232 calculated for each interval. Becauseof the dynamic integration of small individual command incrementsresulting in a smooth, reproducible motion profile, the locations of thelaser dots 2212 appear stationary to the human eye, even though thetrajectory path is created by a moving pulsed laser beam. Although inthe discussion herein above, the laser pulses were synchronized tocommand increment distances between dots 2212, a stationary patternwould still be created even if the time between laser pulses were alittle different than the time between calculated position increments aslong as the galvo mirrors 755, 760 came to a stop at the start of eachperiod at the projection point 2216 beam position.

Visibility of a glowing pattern 2210 formed by a focused moving laserbeam, either continuous or pulsed, is determined by its local averageirradiance, in units of optical power per unit area, along thetrajectory path. This is illustrated in FIG. 23A for continuous laseroperation and in FIGS. 23B, 23C, 23D for pulsed operation. To simplifycalculations, the shape of the focused laser spot 2312 in FIG. 23A is asquare, each side having a dimension a. For the case of cw laseroperation that produces a periodically projected continuous glowing linesection 2310 formed by a continuously moving laser spot 2312 having alinear velocity ν, a projection refresh period T, a spot side dimensiona, and a cw beam power P₀, the average irradiance A₀ of the glowing linesection as seen by a viewer is

A ₀=(P ₀ /a ²)(a/L)=P ₀/(νTa)  (Eq. 1)

Here, the length L of the periodically projected line 2310 is L=ν·T. Forthe case of continuous laser operation, the average output power P_(A)is equal to the cw laser power P₀.

FIG. 23D shows a pulse train 2320 of individual laser pulses 2322 eachhaving a pulse width τ, the time interval between pulses t, and a peakpower P₁. The average output beam power P_(A) of the pulse train 2320 is

P _(A) =P ₁ τ/t.  (Eq. 2)

FIG. 23C shows a periodically projected pattern 2330 having isolatedareas 2332 illuminated during the laser pulses 2322. The projected spotsare blurred over the pulse width τ by the movement of the beam at thelinear velocity ν. If the velocity is constant over the pulse width,then the velocity is equal to

ν=a/τ  (Eq. 3)

And the illumination distribution across each area 2332 has a triangularshape 2340 that occupies a length

b=2a  (Eq. 4)

If the pulses are synchronized with the beam motion control as describedherein above, the isolated areas 2332 appear to be stationary to thehuman eye, and the isolated areas 2332 occupy the same locations in thepath 2334 for every period of projection. In this situation, theseparation s between adjacent areas 2332 is

s=t·ν.  (Eq. 5)

The average irradiance A₁ of a single laser dot in an isolated area 2332as it appears to a viewer eye is

A ₁=(P ₁/2a ²)(a/L).  (Eq. 6)

Noting that for the case of a cw laser beam, the average output power isequal to the cw laser power, P_(A)=P₀, and combining Eqs. (1)-(6) givethe results

A ₁ =A ₀ s/b,  (Eq. 7)

and s/b=t/(2τ).  (Eq. 8)

Eq. (7) says that average irradiance of an individual laser dot in area2332 as viewed by an observer's eye is higher by a factor s/b than theaverage irradiance of a continuously moving laser spot 2312 emitted by acw laser. Hence it is possible to improve visibility using a pulsedlaser beam to produce dots that appear stationary to a user. As anexample, to achieve an increase in the irradiance of 5 to 10 times in aglowing pattern of light seen by an observer, the ratio s/b wouldordinarily be held to at least 10:1.

The discussion above made some simplifying assumptions such as the shapeof the moving laser spot (square rather than Gaussian shape, forexample). If desired, more detailed calculations can be performed toeliminate the simplifying assumptions. In general, the effective spotsize is a function of pulse width, linear velocity, and simplified spotsize: b=F(τ, ν, a).

An aspect of an embodiment is obtaining high visibility of the dots thatappear stationary while keeping within laser safety requirements. Thisis done by adjusting a combination of parameters, including averagelaser power, pulse repetition rate, instant pulse energy, focused laserspot size, distance between the light projector 10 and the object, andthe beam steering angular velocity.

In an embodiment, the relevant laser safety standard in most cases isthe International Standard on Safety of Laser Products IEC 60825-1. Thisstandard defines Accessible Exposure Limits (AEL) by limiting theaverage laser power, the single pulse energy, and the energy per pulsewithin a pulse train for each defined Laser Safety Class. In otherembodiments, other standards or safety guidelines are followed insteadof, or in addition to, those of IEC 60825-1.

For galvanometer-based laser light projectors such as the lightprojector 10, usually the relevant laser quantities from IEC 60825-1 areaverage laser power and single pulse energy. Allowable levels for thesequantities are established for different laser classes. For the lightprojector 10, usually projectors are either class 2 or class 3R. Forprojection of visible wavelengths, the average optical power limits are1 mW for class 2 and 5 mW for class 3R.

According to the 2014 edition of IEC 60825-1, the maximum single pulseenergy for visible light pulses shorter than 5 microseconds is 77 nJ(nanojoules) for class 1 and class 2 and 380 nJ for class 3R.

For a single pulse energy E_(P) and an average power P_(A) of a pulsetrain, the periodicity of pulses is given by

t=E _(P) /P _(A).  (Eq. 9)

Hence for a class 2 laser at the optical power limit of 1 mW and a pulseenergy limit of 77 nJ, the periodicity of laser pulses in a pulse trainmust be separated by at least H=77 nJ/1 mW=77 μs. In this document, thesymbol H is used to represent the maximum allowable periodicity. Manyvalues are possible for the allowable periodicity H according to thestandard being considered.

For pulsed laser operation, a value is obtained for a maximum allowablelinear spacing between projected dots. Spacing between the dots must besmall enough to provide an operator with guidance to align and placeitems in a manufacturing or construction projector. In an embodiment,the spacing s is a constant. The light projector 10 has maximumachievable angular velocity ν_(ang) (in units of radians per second) forthe projected beam of light. In an embodiment, the periodicity t betweenpulses is determined with the equation t=s/(D·ν_(ANG)). In oneembodiment, D is the average distance between the light projector 10 andthe object. Under this condition, the quantities s, D, and ν_(ang) arefixed so that the periodicity t between adjacent laser pulses is alsofixed. In another embodiment, the distance D is taken to be the actualdistance to each point, which then produces a periodicity t that changeswith the distance D.

In an action, one of two branches is taken according to whether theperiodicity t between pulses is less than or equal to the pulse trainperiodicity threshold H. If t≤H, then for an allowable average powerlimit P_(AvLim) and a maximum available peak laser power P_(PkMax), thepulse width r and peak power P₁ are set to

τ=t·P _(AvLim) /P _(PkMax),  (Eq. 10)

P ₁ =P _(PkMax).  (Eq. 11)

If t>H, then the pulse width τ and peak power P₁ are set to

τ=(t/0.7)^(1.33),  (Eq. 12)

P ₁ =P _(AvLim).  (Eq. 13)

The calculated values for the periodicity t, the pulse width τ, and thepeak pulse power P₁ are selected to provide control of the laser whenrunning in pulsed mode. The laser beam is steered by the galvo steeringmirrors 755, 760 in response to signals sent from the DSP 1880. Thetrajectory produced by the galvo steering mirrors 755, 760 issynchronized to the laser pulses.

For cw laser operation, the processor calculates the trajectory of theglowing pattern. The average output power is set less than or equal tothe laser safety limit: P_(Av)≤P_(AvLim). The galvo steering mirrors755, 760 move the laser beam along a predetermined trajectory, takingsteps with free running motion control ticks T as in FIG. 21 .

For both pulsed and cw laser operation, the power monitor assembly 1020monitors the output of the laser monitor to guarantee fail-safeoperation of the system to meet laser safety requirements. In anembodiment, when the light projector 10 is operating in cw mode and theaverage emitted laser power P_(Av) exceeds the laser safety limitP_(AvLim), circuitry in the power monitor 1820 in the optics or frontpanel module 1720 causes the PSoC 1825 to send a signal to the laserdriver PCBA 1732 over the control line 1841 to shut down the laser 710.In an embodiment, when the light projector 10 is operating in pulsedmode, the power monitor 1820 causes the PSoC 1825 to send a signal tothe laser driver PCBA 1732 to shut down the laser if the energy of asingle laser pulse energy exceeds the allowable emission limit for pulseenergy for the given periodicity t, for example, as given in IEC 60825-1or other applicable laser safety standard.

Today, it can happen that a light projector system projects so manypatterns on an object that the time to project all the patterns islarger than the flicker limit, resulting in the undesirable flickereffect described earlier. A way that has been developed for counteringthis problem is for an operator to place a reflective or retroreflectivematerial in the path the projected pattern. The presence of thismaterial is detected by the light projector system and interpreted as acommand by the operator. Such a command might indicate, for example, tozoom in on the region near the detected material, thereby illuminatingonly a portion of the whole pattern and causing the flickering to stop.In another case, the command might direct the light projector to beginprojecting the next pattern in a sequence of patterns. Such a commandmight be used, for example, in a multi-ply layout procedure used withcarbon-fiber composite structures in which a different pattern isprojected for each new ply.

These methods for inserting a reflective material into the path ofprojected beam of light work well for projectors operating in cw mode.However, this method does not in general work for the case in whichstationary dots are projected onto an object at position 2216, as thedots do not necessarily intercept the reflective material. Theprojection of dots is particularly problematic if the reflective patterninserted into the projected light pattern contains multiple separateelements that together provide a coded command in which the commanddepends on the arrangement of the separate elements.

FIGS. 24A, 24B, 24C show three reflective coded patterns 2400, 2410,2420, respectively, having one, two, and three reflective elements 2402,2412, 2422, respectively, that reflect patterns of light 2404, 2414,2424, respectively. If a cw beam of light strikes these reflective codedpatterns, the pattern of reflected light is detected by opticaldetectors such as the SiPM detectors 1385, 1390 and the patternidentified by a processor within the light projector 10. In contrast,when the light projector is operating in the pulsed mode, as illustratedin FIG. 24D, the reflective portion 2432 of the coded pattern 2430 willnot necessarily reflect light from one of the dots 2434. In anembodiment, the operator moves the target along the path 2436 until oneof the reflective elements reflects one of the dots back to the lightprojector 10. In most cases, the reflectivity of the reflective portionof a reflective coded pattern will be relatively much larger than theamount of light reflected from the object. The processors within thelight projector 10 notice this increase in reflected light and, inresponse, cause the light projector 10 to switch to cw mode, projectinga short segment of light 2440 over the coded pattern 2442 as illustratedin FIG. 24E. In an embodiment, the segment of light is long enough toidentify the nature of the pattern within the coded pattern. In anembodiment, the light projector may return to pulsed mode or remain incw mode depending on the nature of the coded message contained in thecoded pattern.

According to another embodiment, another method is provided. The methodincludes: steering a pulsed laser beam to form a first pattern ofstationary dots on an object; placing a reflective target to interceptone of the dots; and detecting a change in reflected light and, inresponse, switching the laser from pulsed mode to continuous-wave (cw)mode.

In addition to one or more of the features described herein, or as analternative, further embodiments of the method may include detecting asecond pattern of laser light reflected from the reflective target whenthe laser is in cw mode and, in response, taking an action based on thedetected second pattern. In addition to one or more of the featuresdescribed herein, or as an alternative, further embodiments of themethod may include the action that steers the pulsed laser beam to forma third pattern of stationary dots on the object, the third patterncovering a smaller area than the first pattern.

According to another embodiment, another device is provided. The deviceincluding a laser operable to produce a pulsed laser beam and acontinuous-wave (cw) laser beam. A beam-steering system is operable tosteer the pulsed laser beam onto an object to create a first pattern ofstationary dots on the object. A reflective target is provided. Anoptical detector is operable to detect reflected laser light. One ormore processors are operable to determine that the detected laser lighthas been reflected by the reflective target and, in response, causingthe laser to emit the cw laser beam and further causing thebeam-steering system to steer the emitted cw laser beam into a segmentof light on the reflective target

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include the one ormore processors being operable to determine that the cw laser beam, whenreflected from the reflective target and detected by the opticaldetector, has a second pattern, the processor taking a further actionbased on the determined second pattern. In addition to one or more ofthe features described herein, or as an alternative, further embodimentsof the device may include the further action that steers the pulsedlaser beam to form a third pattern of stationary dots on the object, thethird pattern covering a smaller area than the first pattern.

According to another embodiment, another device is provided. The deviceincludes a beam-steering system operable to project a pattern of laserlight onto an object, the beam-steering system including a firstgalvanometer operable to rotate a first mirror and a second galvanometeroperable to rotate a second mirror, the first galvanometer furtherincluding a first angle transducer to measure a first angle of rotationof the first mirror, the second galvanometer including a second angletransducer to measure a second angle of rotation of the second mirror.An optical detector is operable to detect laser light reflected theobject. A processor is operable to discern features of the object basedat least in part on the optical power of the reflected laser light andon the measured first angle and the measured second angle. A firstbattery is operable to automatically provide electrical power to thedevice in the absence of electrical power from a power mains.

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include a secondbattery operable to provide electrical power to the device, wherein thefirst battery or the second battery may be removed from or placed intothe device without first turning off power to the device. In addition toone or more of the features described herein, or as an alternative,further embodiments of the device may include a supplemental backupbattery providing temporary backup power to preserve device stateinformation when electrical power is available from neither the batterynor the power mains. In addition to one or more of the featuresdescribed herein, or as an alternative, further embodiments of thedevice may include circuitry to balance electrical power extracted fromthe first battery and the second battery based at least in part oncharge remaining in the first battery and the second battery.

According to another embodiment, another method is provided. The methodincludes: providing a system having a laser, a beam-steering system, anoptical detector, and a first battery; generating laser light with thelaser; projecting the laser light onto an object with the beam-steeringsystem, the beam-steering system having a first galvanometer and asecond galvanometer, the first galvanometer steering laser light off afirst mirror and measuring a first angle of rotation of the firstmirror, the second galvanometer steering the laser light off a secondmirror and measuring a second angle of rotation of the second mirror;detecting with the optical detector the laser light reflected from theobject; discerning features of the object based at least in part on theoptical power of the detected laser light and on the measured first andthe measured second angle; monitoring to determine whether the system isbeing provided with electrical power through a power mains; andproviding the system with electrical power the first battery whenmonitoring has determined that the power mains is not providing thesystem with electrical power.

In addition to one or more of the features described herein, or as analternative, further embodiments of the method may include providing theelectrical system with a second battery and providing the system withelectrical power from the second battery. In addition to one or more ofthe features described herein, or as an alternative, further embodimentsof the method may include adding the second battery to the system orremoving the second battery from the system without first turning offpower to the system. In addition to one or more of the featuresdescribed herein, or as an alternative, further embodiments of themethod may include providing the system with a supplemental backupbattery; monitoring to determine whether the system is being electricalpower from any source; and providing the system with temporary backuppower to preserve device state information when electrical power is notbeing provided to the system from any source.

In addition to one or more of the features described herein, or as analternative, further embodiments of the method may include balancingelectrical power extracted from the first battery and the second batterybased at least in part on charge remaining in the first battery and thesecond battery.

In another embodiment, another device is provided. The device includes abeam-steering system operable to project a pattern of laser light ontoan object, the beam-steering system including a first galvanometeroperable to rotate a first mirror and a second galvanometer operable torotate a second mirror, the first galvanometer further including a firstangle transducer to measure a first angle of rotation of the firstmirror, the second galvanometer including a second angle transducer tomeasure a second angle of rotation of the second mirror. An opticaldetector is operable to detect laser light reflected the object. Aprocessor is operable to discern features of the object based at leastin part on the optical power of the reflected laser light and on themeasured first angle and the measured second angle. A wirelesscommunication system is operable to transmit and receive wireless data.

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include the wirelesscommunication system includes a Wi-Fi transceiver module based on theIEEE 802.11 family of standards, the Wi-Fi module operable to transmitand receive data wirelessly. In addition to one or more of the featuresdescribed herein, or as an alternative, further embodiments of thedevice may include the Wi-Fi transceiver module being operable tocommunicate with Wi-Fi device connected to a network. In addition to oneor more of the features described herein, or as an alternative, furtherembodiments of the device may include the Wi-Fi transceiver module isfurther operable to communicate with a Wi-Fi device not connected to anetwork, the communication made through an access point on the device.In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include the wirelesscommunication system having a Bluetooth transceiver module operable toexchange data wirelessly with a Bluetooth enabled device.

According to another embodiment, another device is provided. The deviceincludes a beam-steering system operable to project a pattern of laserlight onto an object, the beam-steering system including a firstgalvanometer operable to rotate a first mirror and a second galvanometeroperable to rotate a second mirror, the first galvanometer furtherincluding a first angle transducer to measure a first angle of rotationof the first mirror, the second galvanometer including a second angletransducer to measure a second angle of rotation of the second mirror. Afirst optical detector is operable to detect laser light reflected theobject. A second optical detector is operable to detect the laser lightreflected from the object, the second optical detector having a highersensitivity than the first optical detector. A beam splitter is operableto send a first portion of the laser light reflected from the object tothe first optical detector and to send a second portion of the laserlight reflected from the object to the second optical detector. Aprocessor is operable to discern features of the object based at leastin part on the measured first angle, the measured second angle, and onat least one of the optical power of the first portion and the opticalpower of the second portion.

In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include thesensitivity of the second optical detector is at least one hundred timeshigher than the sensitivity of the first optical detector. In additionto one or more of the features described herein, or as an alternative,further embodiments of the device may include a pinhole aperture; a lensoperable to focus the laser light reflected from the object; and apinhole adjustment mechanism operable to adjust the position of thepinhole aperture to pass the focused laser light to the beam splitter.In addition to one or more of the features described herein, or as analternative, further embodiments of the device may include a housing tohold the lens and the pinhole aperture, the housing being at leastpartially covered with a coating to suppress scattering of light betweenthe lens and the pinhole aperture.

According to yet another embodiment, a pinhole assembly is provided. Thepinhole assembly including a pinhole aperture. A pinhole x-y adjustmentmechanism is provided having a first screw and a first spring that eachpush in the x direction against the pinhole aperture, the first springarranged to apply a force opposing the push of the first screw, thepinhole x-y adjustment further having a second screw and a second springthat each push in the y direction against the pinhole aperture, thesecond spring arranged to apply a force opposing the push of the secondscrew. A pinhole z-adjustment mechanism is provided having a tube withexternal threads, a ring with internal threads, and a third spring, thering being placed over the pinhole x-y adjustment mechanism and thethird spring and then screwed onto the tube, the ring constraining thez-position of the pinhole x-y adjustment mechanism while providingaccess to the first screw and the second screw for adjusting the x-yposition of the pinhole aperture.

The term “about” is intended to include the degree of error associatedwith measurement of the quantity based upon the equipment available atthe time of filing the application. For example, “about” can include arange of ±8% or 5%, or 2% of a given value.

The terminology used herein is for the purpose of describing embodimentsonly and is not intended to be limiting of the disclosure. As usedherein, the singular forms “a”, “an” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, element components,and/or groups thereof.

While the disclosure is provided in detail in connection with only alimited number of embodiments, it should be readily understood that thedisclosure is not limited to such disclosed embodiments. Rather, thedisclosure can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of thedisclosure. Additionally, while various embodiments of the disclosurehave been described, it is to be understood that the exemplaryembodiment(s) may include only some of the described exemplary aspects.Accordingly, the disclosure is not limited by the foregoing descriptionbut only by the scope of the appended claims.

What is claimed is:
 1. A device configured to be selectively coupled toa power mains, the device comprising: a beam-steering system operable toproject a pattern of laser light onto an object, the beam-steeringsystem including a first galvanometer operable to rotate a first mirrorand a second galvanometer operable to rotate a second mirror, the firstgalvanometer further including a first angle transducer to measure afirst angle of rotation of the first mirror, the second galvanometerincluding a second angle transducer to measure a second angle ofrotation of the second mirror; an optical detector is operably coupledto the beam-steering system that is configured to detect laser lightreflected the object; a processor is operable to determine features ofthe object based at least in part on the optical power of the reflectedlaser light and on the measured first angle and the measured secondangle; and a first battery is operably coupled to the beam-steeringsystem, the optical detector, wherein the processor is configured toautomatically provide electrical power to the device from the firstbattery in the absence of electrical power from the power mains.
 2. Thedevice of claim 1, further comprising a second battery operable toprovide electrical power to the device, wherein the first battery or thesecond battery may be removed from or placed into the device withoutfirst turning off power to the device.
 3. The device of claim 1, furthercomprising a supplemental backup battery providing temporary backuppower to preserve device state information when electrical power isavailable from neither the battery nor the power mains.
 4. The device ofclaim 3, further comprising power management circuitry to balanceelectrical power extracted from the first battery and the second batterybased at least in part on charge remaining in the first battery and thesecond battery.
 5. A method comprising: providing a system having alaser, a beam-steering system, an optical detector, and a first battery;generating laser light with the laser; projecting the laser light ontoan object with the beam-steering system, the beam-steering system havinga first galvanometer and a second galvanometer, the first galvanometersteering laser light off a first mirror and measuring a first angle ofrotation of the first mirror, the second galvanometer steering the laserlight off a second mirror and measuring a second angle of rotation ofthe second mirror; detecting with the optical detector the laser lightreflected from the object; determining features of the object based atleast in part on the optical power of the detected laser light and onthe measured first and the measured second angle; monitoring todetermine whether the system is being provided with electrical powerthrough a power mains; and providing the system with electrical powerthe first battery when monitoring has determined that the power mains isnot providing the system with electrical power.
 6. The method of claim5, further comprising providing the electrical system with a secondbattery and providing the system with electrical power from the secondbattery.
 7. The method of claim 6, further comprising adding the secondbattery to the system or removing the second battery from the systemwithout first turning off power to the system.
 8. The method of claim 7,further comprising: providing the system with a supplemental backupbattery; monitoring to determine whether the system is being electricalpower from any source; and providing the system with temporary backuppower to preserve device state information when electrical power is notbeing provided to the system from any source.
 9. The method of claim 5,further comprising balancing electrical power extracted from the firstbattery and the second battery based at least in part on chargeremaining in the first battery and the second battery.
 10. A devicecomprising a beam-steering system operable to project a pattern of laserlight onto an object, the beam-steering system including a firstgalvanometer operable to rotate a first mirror and a second galvanometeroperable to rotate a second mirror, the first galvanometer furtherincluding a first angle transducer to measure a first angle of rotationof the first mirror, the second galvanometer including a second angletransducer to measure a second angle of rotation of the second mirror;an optical detector is operably coupled to the beam-steering system andis configured to detect laser light reflected the object; a processor isoperably coupled to the beam-steering system and optical detector, theprocessor being configured to detect features of the object based atleast in part on the optical power of the reflected laser light and onthe measured first angle and the measured second angle; and a wirelesscommunication system is operable to transmit and receive wireless data.11. The device of claim 10, wherein wireless communication systemincludes a Wi-Fi transceiver module based on the IEEE 802.11 family ofstandards, the Wi-Fi module operable to transmit and receive datawirelessly.
 12. The device of claim 11, wherein the Wi-Fi transceivermodule is operable to communicate with a Wi-Fi device connected to anetwork.
 13. The device of claim 12, wherein the Wi-Fi transceivermodule is further operable to communicate with a Wi-Fi device notconnected to a network, the communication made through an access pointon the device.
 14. The device of claim 10, wherein the wirelesscommunication system includes a Bluetooth transceiver module operable toexchange data wirelessly with a Bluetooth enabled device.
 15. A devicecomprising: a beam-steering system operable to project a pattern oflaser light onto an object, the beam-steering system including a firstgalvanometer operable to rotate a first mirror and a second galvanometeroperable to rotate a second mirror, the first galvanometer furtherincluding a first angle transducer to measure a first angle of rotationof the first mirror, the second galvanometer including a second angletransducer to measure a second angle of rotation of the second mirror; afirst optical detector is operably coupled to the beam-steering systemand is configured to detect laser light reflected the object; a secondoptical detector is operably coupled to the beam-steering system todetect the laser light reflected from the object, the second opticaldetector having a higher sensitivity than the first optical detector; abeam splitter positioned to send a first portion of the laser lightreflected from the object to the first optical detector and to send asecond portion of the laser light reflected from the object to thesecond optical detector; a processor is operably coupled to the firstoptical detector, the second optical detector, and the beam-steeringsystem, the processor being operable to detect features of the objectbased at least in part on the measured first angle, the measured secondangle, and on at least one of the optical power of the first portion andthe optical power of the second portion.
 16. The device of claim 15,wherein the sensitivity of the second optical detector is at least onehundred times higher than the sensitivity of the first optical detector.17. The device of claim 16, further comprising: a pinhole aperture; alens operable to focus the laser light reflected from the object; and apinhole adjustment mechanism operable to adjust the position of thepinhole aperture to pass the focused laser light to the beam splitter.18. The device of claim 17, further comprising a housing to hold thelens and the pinhole aperture, the housing being at least partiallycovered with a coating to suppress scattering of light between the lensand the pinhole aperture.
 19. The device of claim 15, further comprisinga pinhole assembly, the pinhole assembly comprising a pinhole aperture,a pinhole x-y adjustment mechanism having a first screw and a firstspring that each push in a first direct direction against the pinholeaperture, the first spring arranged to apply a force opposing the pushof the first screw, the pinhole x-y adjustment further having a secondscrew and a second spring that each push in a second direction againstthe pinhole aperture, the second direction being perpendicular to thefirst direction, the second spring arranged to apply a force opposingthe push of the second screw; a pinhole z-adjustment mechanism having atube with external threads, a ring with internal threads, and a thirdspring, the ring being placed over the pinhole x-y adjustment mechanismand the third spring and then screwed onto the tube, the ringconstraining a z-position of the pinhole x-y adjustment mechanism whileproviding access to the first screw and the second screw for adjustingthe x-y position of the pinhole aperture.